Prior art carboxylic acid syntheses from aromatic ketones by the addition of hydrogen cyanide such as disclosed by Eliel et al. Org. Syn. 33, 7 (1953) involve a reversible step with an unfavorable equilibrum as well as a reduction step. In the process of the present invention the steps are irreversible and no reduction step is required. The process of the present invention thus results in greatly increased yields and higher purity of the desired carboxylic acid. The carboxylic acids which can be produced by the process of this invention are known in the art as useful compounds. For example, 2-(p-isobutylphenyl)propionic acid and 2-(m-fluoro-p-phenyl)phenylpropionic acid are highly active antiinflammatory agents, and 3,4-dimethyoxyphenylacetic acid is useful in preparing papaverine.